If you’re riding the Red Line between Loyola and Roosevelt this weekend, and you witness someone disrobe on your car, try not to worry — that person is (probably) part of the annual No Pants Ride.

“I tell ya, some of the things that I’ve heard from people, some of the older people who have looked at us like ‘What the hell is going on today?’” said organizer Steve Preston. “The facial expressions are wonderful.”

2019 will be year eight for the Chicago edition of the event, which begins noon Sunday at the parking garage adjacent to the Loyola Red Line stop (1209 W. Arthur Ave.). Guests are requested to show up between 11:30 and 11:45 at the top floor of the garage (or the third floor, if weather is poor.)

Wannabe exhibitionists, aspiring improv comedians and fans of non-threatening nudity took to the CTA Red Line Sunday, Jan. 12, for the No Pants Subway Ride. Organizers said at least 110 people took part this year, which was the eighth year the ride has been held in Chicago.

(John J. Kim / Chicago Tribune)

To be clear, you should show up wearing pants.

Beginning at noon, attendees will be divided into groups and then sent on different CTA Red Line runs and train cars. Riders will also be assigned stations where they are to switch trains. Departures begin at 12:30 p.m.

As they approach their respective stops, they will disrobe their lower half on the train, then disembark at their stop, sans pants. Riders then board the following train, which will have some trailing pantsless riders getting off, then boarding the next follower, and so on.

“We divvy up the people in groups over the eight cars (per CTA train),” Preston said. “So multiple people are getting on in different cars, multiple people are getting on at different stops, and (other riders) just don’t realize what the heck is going on until later.”

The ride goes south to Roosevelt, where participants hang out and wait for trailing riders to finish (approximately 1:30 to 2 p.m.). Then, everyone heads back toward Howard, with plans to dine at the Five Guys at Arthur and Sheridan. The burger franchise location has accommodated the pantsless crew during past years.

The No Pants Subway Ride began in New York City as a project of Improv Everywhere. The event has spawned concurrent rides throughout the world, including Chicago’s version.

This is Preston’s second year as the primary organizer of the event here, and he still receives help from Justin Hardesty, who began the Chicago edition years ago.

“The whole idea is to have fun and flabbergast the community … it’s not anything risque. You have to be fully covered under Chicago law. So it’s like, more or less, people who have been running around in bathing suits, but they’re in their underwear,” Preston said.

Last year the event drew about 160 riders, he said. This year, he’s hoping to hit 200 participants. Historically, the colder the weather is, the higher the turnout has been, he said.

For security measures, Preston checks in annually with the CTA, which supports the ride, as well as the Chicago Police Department, which supplies two plainclothes officers that act as security for the ride. Preston also maintains radio contact with six additional “car leaders” to monitor safety.

“We had one year that we got somebody who ended up lunatic-y and tried to be touchy-feely, and he got arrested,” Preston said. “We don’t play any games with this.”

And, for anyone concerned with the sanitation of riding with just one layer, Preston was reassuring, saying returning riders have never found this to be an issue.

“Some people sit, some people stand. Some people are carrying their books and just sitting in the doorway reading a book. Other people just sit there and talk. It’s like another day on the CTA, except you’re ridin’ pantsless,” Preston said. “I have seen people who bring something to put on the seats, but we’ve never had a problem on the Red Line.”